As promised, the answers are:
1. “Belt and braces” = Someone who wears belt and braces is very cautious and takes no risks.
2. “Keep your wig on!” = Tell someone to calm down.
3. “Paint the forth bridge” = Something never ends
4. “Off One’s Trolley” = Mad, out of one’s mind.
5. “Hugger-mugger” = Confused; disorderly.